Cleavage of proenkephalin by a chromaffin granule processing enzyme.
Human proenkephalin generated by means of a recombinant vaccinia virus expression vector was used as the substrate for a putative processing enzyme obtained from bovine adrenal chromaffin granules. The adrenal enzyme successfully cleaved proenkephalin to generate low mol wt enkephalins as well as other enkephalin-containing intermediates. Radioactively labeled proenkephalin prepared with this system was also cleaved; however, under identical conditions bovine proinsulin was not cleaved. These results provide support for the notion that the adrenal trypsin-like enzyme is involved in the processing of proenkephalin in vivo and demonstrate the usefulness of protein substrates prepared by expression vector systems in testing the reactivity and specificity of proposed prohormone processing enzymes in vitro.
Lindberg
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I
Department of Biochemistry and Molecular Biology, Louisiana State University Medical School, New Orleans 70112.
Thomas
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G
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002460:Cell Line; D002837:Chromaffin Granules / Q000201:enzymology*; D002838:Chromaffin System / Q000201:enzymology*; D004745:Enkephalins / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011384:Proinsulin / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism*; D011994:Recombinant Proteins; D012697:Serine Endopeptidases / Q000378:metabolism
D004745:Enkephalins; D011498:Protein Precursors; D011994:Recombinant Proteins; C056943:peptide B; C029992:proenkephalin; D011384:Proinsulin; D012697:Serine Endopeptidases; C060973:membrane-bound adrenal trypsin-like enzyme